This proposal addresses the neurobehavioral development of hydrocephalic children in relation to neuropathology, cognitive development, school achievement, and behavioral adjustment. Study I provides two additional two year follow-ups of a cohort of 125 children with 3 etiologies of hydrocephalus (spina bifida, aqueductal stenosis, intraventricular hemorrhage) and comparison groups (unshunted spina bifida, normals, premature-no IVH) followed yearly over 3 years. Study 2 is an expanded cross-sectional study of MRI and cognitive development in the 3 hydrocephalus etiologies and 3 comparison groups (N=160). Six specific aims will be addressed. Aim 1 (neuropathological correlates of hydrocephalus) expands our ongoing MRI research on neuro- pathological lesions associated with hydrocephalus. Aim 2 (nature of impaired abilities) expands on research showing poorer development of nonverbal skills than verbal skills in hydrocephalic children into cognitive domains involving problem solving and attention. Aim 3 (CNS lesions and cognitive development) addresses relationships of neuro- pathology and variations in cognitive skills. Aim 4 (change over time) addresses the modeling of change on an individual basis and testing of hypotheses concerning determinants of change. Aim 5 (academic achievement) addresses possible dissociations in the school-related abilities of hydrocephalic children. aim 6 (behavioral adjustment) proposes that the effects of hydrocephalus on behavioral adjustment are cumulative, emerging, and related to problems with academic achievement, behavioral disorders, and problem solving deficits. Comprehensive multivariate analyses are proposed. This study is unique because of (a) large, carefully selected cohorts; (b) concurrent longitudinal and cross-sectional designs; (c) simultaneous collection of behavioral and neuroimaging data; (d) multidisciplinary team; and (e) comprehensive multivariate approach to analysis. To study promises to enhance scientific understanding of the influence of hydrocephalus on development and the more general issue of the effect of early brain injury on development.